Can tour guide systems replace interpreting equipment?

Tour guide systems (TGSs) were originally developed for factory and museum tours, and consist of a microphone and headset receivers. The museum guide speaks into the microphone and listeners hear everything via their headsets, meaning that they are free to move around and the speaker has no reason to disturb other visitors by shouting. The appeal of this solution is clear: only those who wish to listen have to, and anyone wanting to hear can do so (at a volume that they choose).